X-ray tube anode seal



p 19, 1944. N; STEWART 2,358,668

- X-RAY TUBE ANODE SEAL Filed Jan. 27, 1942 INVENTOR W mum ATTORNEYPatented Sept. 19, 1944 I STATES TUBE ANoDE SEAL.

Nelson Hist wart; Caldwell, N.' J, 'assfignorfftol rWestinghousejElectric &Manufa,ctuifingCom-" T j may, East Pittsburgh,rag-a, corporation bit Pen'n'sylvania Application llanuary 27,maseriaifnb.42 8,33

3 Claims. (01. 25o 1 49 This invention relatesto'the fabrication of an.

anode for an X-jray. tube, especially to .such

7 anodes which'include a copper rod supportinga press element or: thealloy; known as Kovar or like metal capable of being readily united tothe glass of the press, and the invention relates more particularly tothe joint between the copper rod and the Kovar and the method of formingsuch union.

In the usual type of copper anode using a Kovar seal, the Kovar issoldered to the anode afterthe anode has been machined. In addition tothe fact that some losses are experienced due to poor soldering, thelatter constitutes an extra operation which can be avoided, thuscheapening the manufacturing costs of an anode, according to the resultsattending my researches in this field.

Accordingly, an object of this invention is'to avoid the disadvantagesand inconveniences incidental to the use of asoldered joint between theKovar element and its copper support by eliminating the use of solder inthat connection.

Another object is to cutv down the number of operations in forming theaforesaid joint by uniting the Kovar to the copper at the same time thatthe copper is cast.

A further object is to provide means to produce the cast Kovar-copperjoint in such a manner that the cast product can be readily machined toa shape which facilitates the step of sealing the Kovar element into theglass press by which the anode 'is' eventually integrated with the X-raytube.

Still another object is to provide apparatus 1 which can be used overand over for the fabrication, seriatim, inquantity production, of anodesmade according to the present invention, each of the anodes constitutinga complete anode unit as an intermediate product ready for incorporationin its X-ray tube by the use of substantially conventional machinery.

. duced being capable of being stored, transported and supplied indesired quantities as such.

Other objects and features of the invention will be made apparent tothose skilled in the art as progress is made with the description of theembodiment of the invention selected for illustration in theaccompanying drawing wherein:

, part designated by the reference character H is a copper rod which inthe instance shown is to .gree of heat applied, the copper slug l0 meltsand flows down and around vthetarget H3 in Fig. 1 is a view insideelevation, partly in sec tion, of an anode mien x raytubain theconstrucfon of wlriich the present invention' has'be'en embodied Fig. 2s

assemutortiiacampaneet lin'iits ferment: the anode of Fig. 1 andincluding the crucible in which said assembly is placed ready forsubjection tothe heat of a suitable furnace;

Fig. 3 is a view in sectional elevation, illustrating the assembly ofFig. 2 disposed within the furnace, and showing the parts in theirposition after application of the necessary heat Fig. 4 shows the anoderemoved from the furnace and crucible and partly machined.

Referring now to the drawing in detaiL-the constitute the body of theanode in the completed product, the latter being shown in Fig. 1, whilein Fig. 2 the copper element is indicated as a slug at l0, being as yetunshaped.

On top of the copper slug I0 is then placed a carbon bushing l5, whichserves to hold in place the Kovar element l 6, the latter taking theform of a thimble with a lip l'l. Within this thimble is placed a weightl8 made of metal having a melte ing point higher than that of copper,and having 7 a mass adequate to overcome the buoyancy of the Kovarthimble and accordingly acting to sink it into the copper when thelatter is in its melted state, as indicated at C in Fig. 3.

In operation, when the assembly of Fig. 2 has been placed in the furnacel9 and a suitable deknown fashion, and the weight l8 draws the thimble[6 down into the molten copper and at.

the same time draws the lip I! of the thimble against the top of thecarbon bushing until stopped by engagement of the bottom of the bushingwith the upper surface of the molten copper, at which time all of theparts occupy the position shown in Fig. 3. I r

The crucible I2 and its associated parts may be removed from the furnacel9, and after allowing the copper to solidify, the partly completedanode will be removed from the crucible, when it presents the appearanceshown in Fig. 4, according to which it is clear that I have formed asturdy cast joint between the copper rod H and the Kovar seal l6 at thesame operation as that of casting the copper, thus eliminating thepreviously required step of soldering the seal-forming thimble to thecopper rod.

After turning off ,the lip I! of the thimble IS,

the carbon bushing I5,may be slid oif the Kovar thimble and can be usedas many times as its condition permits, together with the carbon blockI3 I and the crucible l2, these being permanent parts of my novelapparatus. The anode i now ready p to be machined in known fashion,thetop edge of the thimble libeing preferably tapered, as indicated at2| in Fig. 1, where it enters the glass press press 22 to form the Kovarseal in known manner. The anode illustrated in Fig 1 is a completearticle of manufacture, ready for its intended use in an X-ray tube, andis a unit capable of being stored with other like units, transported assuch, and installed at will. p I claim:

1. An anode unit for an X-ray tube comprising a copper supporting rod,acylindrical Kovar metal seal element having oneof its peripheraledgesfor said tube. v

3. A complete anode unit for an X-ray tube, comprising a coppersupporting rod having cast 'cast in said copper supporting rod to embedthe in one end thereof a Kovar metal seal element in the form of athimble, the closed end of said thimble being cast in the copper rod toform a molecular union therebetween; and the open end of said thimblebeing embedded in the glass press for said tube, the other end ofjsaidcopper rod being bevelled and having cast therein a refractory metaltarget.

' 1 NELSON H. STEWART. j

